The Victorian Department of Human Services has issued a national health alert over the outbreak of legionnaires disease at the Melbourne Aquarium.

The number of confirmed cases has risen to seven, with all patients in hospital in intensive care.

Five people are in a critical condition and two are recovering.

Dr John Carnie, from the Department of Human Services, expects more cases of the disease to be detected.

"What we're suggesting is for people interstate who visited Victoria during the relevant period, again just as we've told people in Victoria, if they're concerned about it, if they've been to that vicinity and they are currently ill, to see a doctor and ask to get tested for this disease," he said. http://www.abc.net.au/news/newslink/nat/newsnat-28apr2000-73.htm